Legal charity Reprieve made the comments following allegations in the Guardian newspaper that Mr Miliband sanctioned intelligence-gathering operations by MI6 in countries where there was a risk suspects would be tortured.

As foreign secretary Mr Miliband was always consulted by MI6 before the secret service unit began any “particularly difficult” attempts to obtain information from a detainee held in countries which routinely used torture, the paper claims.

A number of British residents have alleged that they were tortured and abused by foreign states with the complicity of either MI6, MI5 or both.

While MI5 falls under the remit of the Home Office, MI6 is in the purview of the Foreign Office.

Last year Mr Miliband lost a bitterly contested legal case in which he had attempted to prevent publication of part of a court judgement showing that MI5 was aware that British resident Binyam Mohamed was being tortured in Pakistan yet still interrogated him.

At least three British nationals have alleged they were tortured in foreign countries with the collusion of British security services during Mr Miliband’s time as foreign secretary.

Two men were detained in Bangladesh and a third man Azhar Khan claims he suffered torture and abuse in Egypt in July 2008. It is alleged he was hooded, beaten and subjected to electric shocks.

During his five-day ordeal he was repeatedly asked questions about his friends and associates in Britain.

Mr Miliband has stated that FCO files show no evidence of ministers being asked to sanction the three men’s detention.

His spokeswoman said: “David would never ever sanction torture and it is completely wrong to suggest, imply or leave a shadow of doubt otherwise.”

But campaigners said further questions needed to be answered.

Reprieve investigator Clara Gutteridge said: “While David Miliband was foreign secretary, the intelligence services were routinely involved in intelligence-gathering operations involving the abuse of prisoners such as Azhar Khan and others.

“Whether or not the British were technically the detaining power is not relevant and Mr Miliband has yet again dodged the question of his own complicity in torture.

“This is a textbook example of how the British government has repeatedly gone wrong on torture and where it will continue to go wrong until ministers gather the courage to address the problem instead of covering it up.”

Amnesty International UK director Kate Allen said: “Allegations that David Miliband personally authorised interrogations of detainees in countries with poor human rights records show that these decisions went right to the top of government.

“Mr Miliband’s statement is carefully worded and he is clear that he didn’t authorise detention or torture in three specific cases. But the question remains whether he gave his OK to receipt of information or MI6 interrogations in other cases when the Foreign Office would have good reason to believe – or even knew – that detainees had been tortured.”